1. Field of the Invention
This invention relates generally to brake control systems and more particularly, to an anti-lock brake system which includes as an operable part thereof a three way direct drive valve used for the control of the application of fluid under pressure to the brakes of an automotive vehicle.
2. Description of the Related Art
Various types of anti-skid brake systems (ABS) are in existence and operate quite satisfactorily for the purposes intended. Typical of such prior art systems is the utilization of a manually operated master cylinder in conjunction with an electrically controlled valving operation. The electrically controlled valve normally is not operable until a predetermined relationship exists between the pressure of the fluid in the master cylinder and that of the fluid in the electrically operated system.
In numerous such systems, solenoid-type valves are utilized as the electrical or electronically controlled portion of the ABS system.
Typical of such prior art systems are those shown in U.S. Pat. Nos. 4,130,322; 4,838,313; 5,221,126 and 5,244,260.
As above indicated, such systems operate quite well for the purposes intended, however, they are relatively complex and expensive and the valves utilized therein add to the complexity and cost of the overall system.
In accordance with the principles of the present invention there is provided a limited angle rotary to linear direct drive automatic brake control valve for use in ABS systems on automotive vehicles. The valve includes a housing having a first bore longitudinally disposed therethrough and a second bore disposed transversely therethrough and intersecting the first bore. A spool is slidably disposed within the second bore for controlling the flow of fluid under pressure. A motor is disposed within the first bore and includes a limited angle rotary shaft having an eccentrically disposed pin extending therefrom into engagement with a slot in the spool. A spring is disposed within the second bore and continuously urges the spool into engagement with the pin. A source of fluid under pressure is applied to the second end of the spool and means is provided to apply an electrical signal to the motor to rotate the shaft so that the pin moves the spool to control the application of fluid under pressure to a brake within the automotive vehicle.
Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art to which the present invention pertains from the foregoing description taken in conjunction with the accompanying drawings.